Composition



Patented Apr. 21, 1925.

UNITED STATES,

PATENT OFFICE.

WTLLIAM G. LINDSAY, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE CE LLULOTD COMPANY, A CORPORATION OF NEW JERSEY.

coMrosrrIoN.

No Drawing. Original application filed August 9, 1922, Serial No, 580,699. Divided and this application filed March 22, 1923. Serial No. 626,760.

for is that which will not permit-of a self sustaining combustion, after the application of a flame at ordinary or normal temperature. This degree .of non-inflammability will however, be varied according to desired conditions.

Ihave discovered that inflammable materials which permit-of a self sustaining com' bustion by the application of a flame at ordinary or normal temperature may be prevented from burning under ordinary conditions and rendered non-inflammable provided there is present in suitable combination a heat absorbing compound capable of absorbing or taking up through decompositioii, volatilization, or other change, all or the major part of the heat that would be necessary to raise the material or its components to the point at which ignition could 'be sustained.

-This heat-absorbing, or endothermic, substance or compound should be of such nature that it will decompose, or otherwise be in condition to absorb heat before or when the temperature of combustion of the materialv to be rendered non-inflammable has been reached. The absorption of heat will thus proceed at such a rate as to prevent the combustible material from attaining its temperature of ignition. The endothermic substance or compound will also be selected having. in view. other characteristlcs besides its heat fabsorbing capacity on decomposition in that it may be desired to impart other properties to the resultant product. The relative proportions of the combustible substance,'i. e., thesubstance to be rendered non-inflammable, and endothermic or heat absorbing substance, will be vanedsome what to meet conditions of. strength, plasticity, transparency, or other desirable characteristics, but in general will be dependent upon the amount of decomposition, in heat unit equivalents, that can take place at or below the temperature at which combustion could be sustained by the exothermic compound if the heat of combustionwere not absorbed at a greater rate than that at which it could be liberated. The general rule is that a sufiicient quantity of endothermic substance should be employed to absorb upon its decomposition a suflicient amount of heat to prevent a sustained combustion of the said exothermic substance.

. In carrying out my invention, any one of a number of products may do the same. The

characteristics of these products may vary from that of a hard, non-moldable, dense solid sheet material which may be used for cutting out various objects such as brush backs, mirror backs. knife handles, etc., to

that of a thin, highly flexible product The exothermic substance which I propose to use will be nitrocellulose, acetylcellulose, or some cellulosic ester ether, derivative or compound.

In the following examples I give such proportions as will be applicable to compounds containing nitrocellulose, as this is the most inflammable of the cellulose derivatives and any substance that may be incorporated with the'nitrate for the purposeipf reduc-'- ing, limiting or preventing combustion will be effective with other compounds of cellulose, and as a matter of fact, with cellulose *itself.-' Y Y The permanent of non-volatile solvents generallyqreferred to as the plasticizing agents and which are to be combined with the pyro'xylin or other cellulose derivative sary gohversion, etcfiin the course of manufacture, should be of such nature that the 'for' the/ purpose of bringing about the necespoint of ignition is relatively high. In my matic phosphate, as for instance liquid tricresylphosphate, I add a sufficient amount of an endothermic compound, sothat when a flame is applied to the resultant product the heat will be absorbed at such a rate as to prevent the material from sustaining ignition (without the application of heat from an external source.) 7

The group'of compounds which I designate as endothermic may be either organic or inorganic in composition. Of the in I organic compounds I have found that there are various acid, basic and neutral salts produced through the combination of one or more of the following acids, with various metallic bases. The following are typical of these. acids: Phosphoric, oxalic, fiuoric, silicic, hydrosilicic, acetic, boric, sulphuric, tartaric, citric,'hydrochloric, formic, and

1 combined with metals of the alkali, alkali earth, or sesquioxide group such as: am-

monium, potassium, sodium lithium, calcium,

magnesium, barium, aluminum, iron, nickel, zinc, chromium, etc.

In selecting a compound of the class described, the properties other than that pertaining to its endothermic value are to be taken into consideration. While it is possible to make noninfl'ammable materials by salts, these have in the majority of cases such limited value and use, that under ordinary circumstances their selection would be confined to very special applications, as compounds like boric acid, ammonium oxalate and magnesium sulphate are examples of water soluble endothermic compounds having definite use and application. Also in the matter of action on the pyroxylin itself, I have found that certain basic and in some cases acid compounds, which are soluble in either water or alcoholic solvents, tend to exert a decomposing action and in some cases prevent solubility. I pre fer in most cases to use a compound which is substantially insoluble in water and which is either substantially insoluble in the alcoholic menstrua employed or very freely soluble. Partial solubility in the solvent may tend to separation or precipitation on the surface of the finished material.

Of the organic compounds I have found that hexachlorethane, C Cl and oxamid satisfactory results by the use of Alophanc', Al O 3SiO 5H O;

Colemanite, Ca B O .5H O;

Chrysocolla, CuSiO QI LO;

Illexite, Na O2Ca05B O 16H O;

Vivianite, Fe (P0 .8H O;

lVavellitc, etc. Al (OH) 3 (P0 .4 H O.

In using these natural compounds, it is necessary to reduce them to a very fine state of subdivision. The particles should be reduced to the size of 1/600 of an inch or less to produce the best results.

lVhile it is possible to produce satisfactory results with a natural mineral compound, more satisfactory results are to be obtained from the use of a compound of the same composition produced synthetically. I refer particularly to synthetic, ulexite and synthetic colemanite. In the use of the synthetic article, it is not necessary to use such a high proportion, the temperature of decomposition apparently being much lower which apparently increases the heat absorbing capacity.

As specific examples of the compounds of the groups .just described I may specify the following:

Aluminium fluoride, Al F .7H O.

Aluminum phosphate, AlPO .XH O.

Aluminum hydrate, Al O .3H O.

Basic aluminum acetate, Al (C H O OH.

Berillium acid phosphate, BeHPO 2H O.

Boric acid, B(OH) Calcium phosphate,- CaHPO 2H O.

Calcium sulphate, CaSO 2H O.

Calcium tartrate, CaC H O 4H O.

Calcium citrate, .Ca (C l-LO AH O.

Calcium borate, (2CaO .3B .5H O.

Hydrazine sulphate, N H .H SO

Lithium phosphate, Li I o .H O.

Magnesium phosphate, MgH O,.7H O.

Magnesium oxychloride, Mg OCl 16H O.

Magnesium sulphate, MgSO KTH O.

Nickel phosphate, Ni (POJ JTH O.

Zinc oxychloride, ZnoflZnCl xH O.

Aluminum oxychloride,

, Al O 3AlCl 3H O.

Ammonium oxalate, (NHQ C O H o.

Ammonium aluminum fluoride,

AlF (NHQ Of the above compounds, I find the most satisfactory results are produced by the use of aluminum phosphate, calcium sulphate,

mine the temperature at which it decomposes and to determine its heat absorbing power in a suitable calorimeter. When tested in such apparatus the compound should show a minimum heat absorbing value corresponding to about 269 B. t. 11. per pound, that is, one pound of the compound should absorb approximately 260 B. t. u. when heated from ordinary temperature to approximately200 G. Its decomposition point should be from approximately 110 to 250 C. In general the proportion of endothermic compound to be employed will depend upon its heat absorbing value and upon the de ree of non-inflammability to be attained. alcium sulphate CaSO,2H,O when tested according to this method will show a heat absorbing value of 297 B. t..u. per pound when heated up to 200 C. or thereabouts; calcium toughness and moldability in similar degree to the usual varieties of celluloid, manufactured in the form of ivory, opaque colors and the like.

In the manufacture of these non-inflammable compounds I proceed substantially as in the manufacture of ordinary pyroxylin plastic materials incorporating the endothermic compound with the soaked or col- 'loidized mass of pyroxylin and liquid tricresylphosphate prior to final mastication on the rolls. This incorporation may be effected in kneaders or the endothermic compound may be directly added during the course of mastication on the rolls. The endothermic compound may also be incorporated with the pyroxylin in the same operation in which the liquid tricresylphosphate isincorporated, the method for which is described in my U. S. Patent No. 1,233,374, granted'July 17, 1917.

In the choice of liquid volatile solvent, I

, pyroxylin.

may select any one or a combination of a number of the common ordinarysolvents, such as methyl alcohol, ethyl alcohol, acetic ether, acetone, amyl acetate, or the various commercial grades and mixtures of these compounds as are ordinarily found upon the market.

In the manufacture of the flexible non-inflammable compound having the properties of leather and the like, I prceed as in the example specified but instead of employing 7 5 parts of liquid tricresylphosphate, I increase the amount to 200 parts to 100; parts Material of this composition may be worked up according to the usual method for the manufacture of pyroxylin plastic compounds and produced in the form of sheets by shaving from a block, or it may be dissolved in a suitable proportion of solvent such as wood alcohol, acetone and the like and spread upon a suitable surface such as a textile fabric, leather and the like.

' This application is a division of my application Serial No. 580,699, filed August 9,1922.

I claim: 7

1. A composition comprising a cellulosic material and an aluminum fluoride.

2. A composition comprising a cellulosic material and an aromatic phosphate in admixture with an aluminum fluoride.

3. A composition containing a cellulosic ester and an aroma ic phosphate and in close association therewith an aluminum fluoride.

4:. A composition containing a cellulose ester and an aluminum fluoride.

5. A composition containing a cellulose ester and tricresylphosphtzte in admixture with an aluminum fluoride.

6. A composition containing pyroxylin and an aluminum fluoride.

7. The process oi making a non-inflammable material which consists in mixing a cellulose derivative with an aromatic phosphate and with an aluminum fluoride.

8. A composition comprising a cellulose derivative and ammonium aluminum fluoride.

'9. A composition comprising a cellulose derivative, an aromatic phosphate and ammonium aluminum fluoride.

10. A composition comprising a pyroxylin, tricresylphosphate and ammonium aluminum fluoride.

11. A composition comprising a cellulose derivative, a plasticizing agent and a flu orine compound of aluminum which absorbs heat on decomposition.

WILLIAM G. LINDSAY:

Certificate of Correction.

-- It is hereby certified that in Letters Patent No. 1,534,651, 1925, upon the application of William G. Lindsay,of Newark, New Jersey, for an improvement in Composition, errors appear in the printed specification requiring correction as follows: Page 1, line 71, for the words do the same read be the aim; and'line 104, for the Word of read or; page 2, line 35,'after the Word sodium insert .a comma; same page, line 107, that the said Letters Patent should be read with these corrections same may conform to the record of the case in the Patent Office.

Signed and sealed this 30th day of J une,'A. D. 1925.

. KARL FENNING,

[sEAn] Acting Uomnm'ssz'oner of Patents,

granted April 21,

therein that. the

for AI O BH O read 111 0 317 0.) and Q 

